Leaded gasoline containing aromaticsubstituted esters



3,083,088 LEADED GASOLINE CONTAINING AROMATHC- SUBSTITUTED TESTERSDennis R. Carlson, Park Forest, Everett N. Case, Hotnewood, and SeymourI-I. Patinkin, Chicago, ilh, assignors, by mesne assignments, toSinclair Research inc, New York, N.Y., a corporation oi Deiaware NoDrawing. Filed June 15, 196i Ser. No. 36,150 9 Claims. (Cl. t t-69) Thisinvention relates to an improved gasoline composition which is of highoctane number, which contains a lead compound as an anti-knocking agent,and also contains an octane rating booster.

By and large, modern gasolines for use in spark-ignited internalcombustion engines, e.g., automotive and airplane engines have an octanenumber of at least 85 RON, that is, as determined by the researchmethod. Almost Without exception producers of gasoline usenon-hydrocarbon agents to raise the octane number of the gasoline tosuppress knocking. Generally this agent is an alkyl lead compoundespecially a tetra-lower alkyl lead, usually a small amount within therange from about 0.5 to 3.0 cc. per gallon, or even as much asapproximately 5 or 6 cc. per gallon. Tetra-ethyl lead is the most widelyused antiknock agent, and is effective in raising the octane and therebyreducing the knock caused by abnormal combustion of gasoline of inferioroctane rating. Other lead compounds, such as the lower-alkyl leadcarboxylates disclosed in copending application S.N. 855,006, filedNovember 24, 1959, are useful as anti-knock agents. However, thequantity of lead compound which may be used in a gasoline is limited bydecreasing efiectiveness at higher percentages, and by the fact thatlead compounds cause lead-containing deposits in the cylinders as wellas by economic, health and legal considerations.

Several methods are used for determining the octane rating of a gasolineand each method usually gives a different figure; for example, the motormethod of determining octane rating generally gives a lower figure thanthe research method. The spread between the two figures is termed thesensitivity of the fuel. Gasolines are sold on the basis of theirresearch octane number but the make of the car and the type of drivingdetermines whether it operates closer to the motor method or researchmethod rating; however, the road octane is usually, numerically, in thespace between the two. A gasoline having motor methodand research methodoctane numbers which are closer is less sensitive in its performance tovariations in operating conditions.

In accordance with this invention, certain gasolinecompatible, i.e.,soluble, miscible or dispersible, aromatic esters are incorporated in aleaded gasoline as an octane booster. The improvement in the gasoline issometimes greater in the motor method of determining octane rating andsometimes greater when the octane is determined by the research method.The fuel may have less spread between its research method number and itsmotor method number, and would accordingly be considered as lesssensitive.

The ester incorporated in gasoline according to this invention is aprimary or secondary monoor di-aryl substituted lower alkyl ester of alower carboxylic acid, that is, one which contains the residues of alower carboxylic acid and a primary or secondary lower aliphatic alcoholhaving an aryl substituent. The ester may be represented by in which Ris a monovalent hydrocarbon radical, preferably of 1-6 carbon atoms andeither or both R and R are hydrocarbon-ring aryl radicals of up to 10carbon atoms in the ring structure, that is, phenyl or naphthyl. If oneof R or R is non-aryl, it is a hydrogn or monovalent hydrocarbonradical, e.g. an alkyl radical of 14 carbon atoms. The hydrocarbonradicals and the carbon atom adjacent R may be substituted, for examplewith alkyl, alkoxy or hydroxy. The R group may be aryl or lower alkyl,preferably a lower alkyl group having 1-4 carbon atoms. The selectedsubstituents will usually provide an ester of up to about 20 carbonatoms. The acid residue or acyl group 2 to 7 carbon atoms. Exemplarypreparations of useable esters are as follows:

PREPARATION OF oc-PHENYL ETHYL ACETATE To a solution of 122 grams (1.0mole) a-phenyl ethyl.

alcohol and 95 grams (1.2 mole) pyridine in 200 ml. anhydrous ether wasadded dropwise ml. (1.2 mole.) acetyl chloride. The reaction occurredimmediately with evolution of heat and precipitation of pyridinehydrochloride. The heat of reaction maintained the temperature at 40 to45 C. through most of the addition. The reaction mixture was allowed tocool to room temperature after which an equal volume of water was addedto the reaction mixture to dissolve the pyridine hydrochloride andhydrolyze any unreacted acetyl chloride. The ether solution was washedwith dilute NaHCO solution, and then water, and dried over anhydrousMgSO The ether was stripped off and the crude product distilled underreduced pressure.

The fraction boiling at 73 C. at 3.0 mm. Hg (220 C. at 760 mm. Hg) wascollected for a 92% yield of a-phenyl ethyl acetate. 2

ANALYSIS [nnNsr'rYgirozes] Cale. Det.

Sap. equiv 342 332. Percent C 73. 25 73. 22 Percent H 7. 33 7. 34

PREPARATION OF 1,2-DIPHENYL ETHYL Toa solution of 50 grams (0.25 mole)1,2-diphenyl ethyl alcohol and 24 grams (0.3 mole) pyridine in 100 ml.anhydrous ether was added dropwise 22 ml. (0.3 mole) acetyl chloride.The reaction occurred immediately evolving heat and precipitatingpyridine hydrochloride. The heat of reaction held the temperature at40-45 C. through most of the addition of ace-tyl chloride. After coolingthe reaction mixture to room temperature an equal volume of water wasadded to dissolve the pyridine hydrochloride and hydrolyze any unreactedacetyl chloride. The ether solution was Washed with dilute NaHCOsolution and then Water, and dried over anhydrous MgSO After strippingoi the ether the crude product was distilled under reduced pressure.

The fraction boiling at 122 C. at 0.8 mm. Hg (319 C. at 760 mm. Hg)(reported Hauser, Shivers and Skell, JACS 67, 409412 [1945], B.P. 312 C.at 760 mm. Hg) was collected for a 75% yield of 1,2-diphenyl ethylacetate.

ANALYSIS [DENSITY2+=1.0794] Cale. J Det.

Sap. equiv 234 210 Percent C 80. 00 80. 46 Percent H 6. 67 6.76 a

The ester is included in the gasoline composition in the ratio of fromabout 1 to 50 moles of ester per mole of lead compound and sufiicient toincrease the octane number of the leaded gasline. The molar ratio ofester to lead compound is preferably about 2 to 40. In terms of volume,the fuel usually contains about 0.1 to 3 volume percent of the ester,preferably about 0.2 to 1.5%, and in amount suflicient to increase theoctane rating of the fuel. The concentration of the additive isimportant in that larger percentages may decrease the octane rating ofthe gasoline below the rating of the base fuel. Also, the optimum rangeof effectiveness of the octane booster varies with the lead content ofthe gasoline. In general, with greater amounts of, for example,tetraethyl lead, not only is the octane increased, but the octaneboosting ability of the ester is also increased and the optimum rangefor this additive is slightly raised.

Gasolines are usually blends of low boiling mineral oil hydrocarbonfractions derived by distillation, cracking, and other refining andchemical conversion processes practiced upon crude petroleum. Thegasoline will contain varying proportions of paratfins, olefins,naphthenes and aromatics and generally will boil primarily in the rangeof about 100 to 425 F. The gasoline of this invention has aromaticcomponents which are at least about volume percent, preferably at leastabout 40 percent of the hydrocarbon fuel. A typical premium gasolinebesides a small amount of lower-alkyl lead compound as an anti-knockagent, may also contain small amounts of other non-hydrocarbonconstituents used to impart various properties to the gasoline in itsuse in internal combustion engines, e.g. scavengers, corrosioninhibitors, etc.- Such gasolines frequently have a research methodoctane number of about 90 to 105 and a motor method octane number ofabout 8098. The most widely used tetra-lower-alkyl lead compound addedto gasolines as an anti-knock agent is tetra-ethyl lead. TEL Motor Mixis used in commercial practice to add tetraethyl lead and scavengers tothe gasoline. Motor Mix contains 59.2% tetra-ethyl lead, 13.0% ethylenedibromide, 23.9% ethylene dichloride and 3.9% hydrocarbon diluent, dyes,etc. Several gasoline blends were used in the examples and testsreported below. Base gasoline M was a naphtha reformate distillationtower bottoms fraction which had an API gravity of 34.1

and contained 25.1% paraflins, 3.2% naphthenes and 71.7% aromatics. Thefraction had an ASTM distillation of:

IBP F 313 50% F 334 F 368 EP F 442 Rec. "percent" 98.5 Res. do 1.0 Lossdo 0.5

Gasoline blend D comprised 28.4% of these tower bot-- toms, 28.4%lightfiuid catalytically cracked gasoline, 19.0% mixed xylenes, 19.0%alkylate fuel and 5.2% butane. This gasoline had an API gravity of 53.0and a bromine number of 35.0. It analyzed as 34.9% paraffins, 15.1%olefins, 7.1% naphthenes and 42.9% aromatlCS.

Its ASTM distillation was:

13? F..- 92 10% F 133 50% F 256 90% F 329 EP F 403 Percent rec 98.0Percent res 1.0 Percent loss 1.0

Gasoline blend E had a bromine number of 38.5 and and analyzed as 7 Vol.percent Parafiins 34.3 Olefins 27.2 Naphthenes 4.7 Aromatics 33.8 Sulfur(weight percent) 0.0213

Samples of these base gasolines were obtained and mixed with varyingamounts of tetraethyl lead and phenylsubstituted lower alkyl esters oflower carboxylic acids. The octane determinations for each sample arereported in Table I below. Samples 1-6 and 71-76 contained 2.9 cc./gal.TEL added as Motor MiX. Samples 1116 and 41-46 contained 3 cc./ gal. ofpure tetraethyl lead. The rest of the samples contained 6 cc./gal. ofpure tetraethyl lead.

a Table I BASE: BLEND E (2.9 00. TEL/GAL.)

V 1 Octane Change from base 0 Sample Additive percent Motor ResearchMotor Research method method method method 1 None 88.5 99.5 2a-ptiicenyl ethyl ace- 0.25 88.4 99.6 0.1 +0.1

Table IContinued Table l-Continued BASE; BLEND D (a co. TEL/GAL.) BASE:BLEND D 0o. TEL/GAL.)

V 1 Octane Change from base V01 Octane Change from base 5 SampleAdditive per sample Addmve 2%; Motor Research Motor Research cent MotorResearch Motor Research method method method method method method methodmethod 91 None 94.3 106.5 11 None 92.4 109.5 12 a-ltfllenyl ethyl ace-0.25 92.7 103.7 +0.3 +0.2 5. 5533 94.8 105.9 +0.5 +0 4 103-5 0 94.9107.1 +0.0 +0 0 i823 ig-g 95.5 107.3 +1.2 +0 8 9217 10412 +03 +07 +0 8BASE: BLEND D (0 0o. TEL/GAL.) BASE: BLEND D (0 CO. TEL/GAL.)

None 04.5 106.4 "6-- None 95.0 10 6111201312; e thyl 1.0 95.1 100.0 +0.6.2 a-phenylethylace- 0.50 06.0 106.3 95.1 106.9 5 tate- 0 95.0 100.7+0.5 +0 3 95.1 100.7 +0.0 +0 3 g M O 7 95.0 100.9 +0.5 +0 5 BASE:FRACTION M 0 00. TEL/GAL.)

BASE: BLEND D (6 CC. TEL/GAL.) 1H 1030 112 fi-rghenyltethyl 1.25 94.7103.4 +0.5 +0.4

6112037 8 31 None 94.5 105.9 32--. an enyletnyince- 1. 75 90.0 107.4+2.1 +1.5 a 0. 95.2 103.6 1.0 0.6 9549 95.0 100.7 11.4 1:07 39-; 95.4103.0 +1.2 +0.0 107 1 +231 +132 95.4 105.5 +1.2 +0.5 90.3 107 0 +1.8+1.1

3 The above examples, which are to be considered 111110- (3 OG TEL/GAL)trative only and not limiting, show that the addition of the enumeratedesters to a leaded gasoline boosts the 921 1024 octane rating ofgasoline fuels. 92.3 102.5 +0.2 +0.1 It is claimed; 92.8 102.7 +0.7 +0.335 1. A leaded gasoline consisting essentially of base Egg g ig-g i8 2hydrocarbon gasohne containing at least about 30% aroig 102:7 1 matichydrocarbons, a small amount of lower alkyl lead anti-knock agentsufficient to reduce knock and about BASE. FRACTION M (6 TEL/GAL) 40 lto 50 moles per mole of lead compound and sufliclent to improve theoctane rating of the leaded gasoline of N 94 3 103 4 agasoline-compatible aryl substituted lower alkyl ester g g 135* 1 1031715 ""153 of a lower carboxylio acid of u to about 20 carbon atoms tatc.and having the formula:

1.50 95.1 103.0 +0.8 +0.2 1.75 94 s 103.0 +0 5 +0.2 H H 2.00 95 1 103.5+0 23 +0.1 a 2.25 955 103.8 +1.3 +0.4 2.50 95 7 103.8 +1 4 +0.4 H i H2.75 95 0 103.7 +0 7 +0.3 7 0 95 5 103-6 2 in WhlCh R is a monovalenthydrocarbon radical, R

and R are selected from the group consisting of hydro- BASE: BLEND D/GAL.) gen and monovalent hydrocarbon radicals, with the proviso that atleast one of R and R is a hydrocarbon-ring 01 None 95.1 105. 7 a ylradical 0t up to 10 carbon atoms in the ring structure. 02"--- fl-i g y105-5 2. A gasoline composition according to claim 1 1n 95,3 1 5,7 0which R has 1 to 6 carbon atoms.

3 105-7 0 3. A gasoline composition according to claim 1 con- 58 105.9+0.7 +0.2 90.0 1059 +0.9 +0.2 taming about 2 to 40 moles of ester permole of lead 95.0 105.7 +0.5 0 95.9 100.0 +0.8 +0.5 compound 4. Agasoline composition according to claim 1 containing at least about 40%aromatic hydrocarbons. BASE: BLEND E 2.9 00. TEL/GAL.) 6O 5. A gasolinecomposition according to claim 3, containing at least about 40% aromatichydrocarbons in which the ester is an acetate.

-1 None 88.4 99.4 i2..-" 1,2-diphenyl ethyl 0.50 88.6 99.5 +0.2 +0.1 6.A gasoline composition according to claim 5 in acetate 8&6 99A 0 whichthe ester is a-phenyl ethyl acetate.

.1 5 7. A gasoline composition according to claim 5 in 88:8 9910 i014 1which the ester is fi-phenyl ethyl acetate.

8. A gasoline composition according to claim 5 in BASE: BLEND D (6 CGTEL/GAL) which the ester 1s 1,2-d1phenyl ethyl acetate.

9. A gasoline composition according to clam 5 in which the ester is,B-phenyl ethyl benzoate.

s1 None 94.9 105.0 82--. m g r fiz yl ethy 1.50 9 100.0 +0.9 +0.4References Cited in the file of this patent 2. 97.1 100.2 +2.2 incFOREIGN PATENTS 1063 42,139 Australia Oct, 8, 1958 571,921 Belgium Oct.10, 1958

1. A LEADED GASOLINE CONSISTING ESSENTIALLY OF BASE HYDROCARBON GASOLINECONTAINING AT LEAST ABOUT 30% AROMATIC HYDROCARBONS, A SMALL AMOUNT OFLOWER ALKYL LEAD ANTI KNOCK AGENT SUFFICEINT TO REDUCE KNOCK AND ABOUT 1TO 50 MOLES PER MOLE OF LEAD COMPOUND AND SUFFICIENT TO IMPROVE THEOCTANE RATING OF THE LEADED GASOLINE OF A GASOLINE-COMPATIBLE ARYLSUBSTITUTED LOWER ALKYL ESTER OF A LOWER CARBOXYLIC ACID OF UP TO ABOUT20 CARBON ATOMS AND HAVING THE FORMULA: